Space heating apparatus

ABSTRACT

A space heater preferably for mobile units such as automobiles and trailers includes a burner having a combustion chamber which is supplied with combustion air by an axially arranged rotatable fan. The construction is characterized by an arrangement of a blower or air compresser for the combustion air and the exhaust passages for the combustion gases in axial alignment and with a precombustion chamber connected radially into the combustion chamber. The heat exchange portion includes an axially elongated relatively flat passage for the combustion gases and a surrounding chamber for the space air to be heated which is also of relatively flat or narrow construction. A fuel supply system for the space heater includes an electromagnetic piston pump which is connected to a current source in a circuit which is controlled by an interrupter operated off the electric fan motor driving the fan for the combustion air. Current is supplied to the electromagnetic piston pump cyclically in order to provide a pumping action of the fuel to the fuel supply line in a cyclic manner in order to provide the desired combustion conditions within the combustion chamber.

United States Patent Siegfried Kofink [45] Patented [73] Assignee Jan. 26, 1971 J. Eberspacher Esslingen, Germany [32] Priority Sept. 8, 1967 [3 3] Germany [31] 1,679,193

Continuation-impart of application Ser. No. 757,550, Sept. 5, 1968, now abandoned.

[54] SPACE HEATING APPARATUS 3,174,277 3/1965 Hettich 237/12I3X 3,273,799 9/1966 Fairbanks et al. 237/12.3X 3,339,617 9/1967 Saha 431/263 3,402,764 9/1968 Fairbanks 237/12.3X

Primary Examiner-Edward G. Favors Attorney-McGlew and Toren ABSTRACT: A space heater preferably for mobile units such as automobiles and trailers includes a burner having a combustion chamber which is supplied with combustion air by an axially arranged rotatable fan. The construction is characterized by an arrangement of a blower or air compresser for the combustion air and the exhaust passages for the combustion gases in axial alignment and with a precombustion chamber connected radially into the combustion chamber. The heat exchange portion includes an axially elongated relatively flat passage for the combustion gases and a surrounding chamber for the space air to be heated which is also of relatively flat or narrow construction. A fuel supply system for the space heater includes an electromagnetic piston pump which is connected to a current source in a circuit which is controlled by an interrupter operated off the electric fan motor driving the fan for the combustion air. Current is supplied to the electromagnetic piston pump cyclically in order to provide a pumping action of the fuel to the fuel supply line in a cyclic manner in order to provide the desired combustion conditions within the combustion chamber.

PATENIED JAN 2 61911 SHEET 2 [1F 2 MEI INVENTOR. 5 56/59/50 KOF/N/f SPACE HEATING APPARATUS CROSS REFERENCE TO RELATED APPLICATION This invention is a continuation-in-part application of Ser. No. 757,550, filed by the present inventor on Sept. 5, I968 and now abandoned.

SUMMARY OF THE INVENTION This invention relates in general to the construction of space heaters and in particular, to a new and useful space heating apparatus particularly for vehicles which include a burner, a combustion chamber, and a heat exchanger arranged in an axial orientation and wherein the heat exchanger portion comprises a substantially flat axially elongated inner passage for the combustion products and a surrounding flat outer passage for the space air to be heated.

Space heaters for mobile units as motor vehicles, boats, airplanes, trailers and the like must meet special requirements because they are used not only when the vehicle is moving but also as stationary heaters. Thus, for example, the exhaust must be so conducted that the poisoning of the occupants of the vehicle will be avoided even when the vehicle is standing still. In addition, a high efficiency of the combustion and a good heat transfer are particularly important for such heating apparatus because the arriount of fuel that can be carried is limited. Finally, such heaters must be easy to assemble and disassemble since they are principally installed as an accesso- Space heaters are known which are characterized by compact design and good efficiency. In a known arrangement the axial arrangement of the combustion air compressor of a combustion chamber and of the after combustion chamber in combination with the known means for the formation of combustion air cyclonic flow results in a particularly good efficiency of the heater. But the known heaters had the disadvantage that the space required for the installation is too great. In addition, the heat transfer arrangements are not the optimum.

In accordance with the present invention, there is provided a space heater of substantially flat construction. The space heater includes a motor blower arranged at one end which forms the wider central portion of the heater and discharges air for combustion axially into a combustion chamber. The combustion fuel is supplied to a precombustion chamber where initial combustion takes place and the fuel products and the precombustion gaseous products are discharged into the central axially arranged combustion chamber which also receives axially directed combustion air. The axial combustion chamber discharges centrally into a heat exchanger formation which is also relatively flat but which includes flow passages which widen in two radial diametrically opposite directions away from the central passage connecting the combustion chamber. The side passages converge to a central discharge conduit at the opposite end.

A chamber for the space air to be heated surrounds the flat heat exchanger and is of similar construction. Air to be heated is directed through one side of the space air chamber and permitted to flow through partial paths around the combustion chamber and around the heat exchanger portion of the device before it exits in a heated condition from an opposite side of the flat heater construction. The construction permits optimum heat transfer but requires a minimum of installation space. The flat design of the heat exchanger not only permits favorable installation in a mobile unit but permits a considerable improvement of total heat transfer which can be achieved. The use of a precombustion chamber which extends radially into the central axially elongated combustion chamber is advantageous for increasing the total efficiency of the device. The device is advantageously arranged with a known electromagnetic piston pump which is controlled by an interrupter arranged on the motor of the combustion air compressor of the heater. With such an arrangement, the fuel flow according to the invention is controlled to provide for optimum efiiciency of combustion operation within the heater. The heater design is particularly advantageous for the relatively small size foreign type automobiles because of its space saving feature. In addition, it is very advantageous for use in boats and similar arrangements. The heater will operate at high capacity with relatively little power.

Accordingly, it is an object of the invention to provide a space heater which includes a flat axially elongated heater housing having a blower mounted at one end for directing air into a combustion chamber which is axially and centrally located at this end of the housing, the interior of the housing including an axially elongated combustion gas pass for the gases generated in the combustion chamber and as surrounding passage for the space air to be heated.

A further object of the invention is to provide a space heater of a flat construction throughout so as to occupy a minimum of space and be particularly suitable for small space installation and which has a heat exchanger flow path which is defined by flat passages for both the combustion air and the air to be heated.

A further object of the invention is to provide a space heater which is simple in design, rugged in construction and economical to manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. 1 is an axially sectional view of a space heater constructed in accordance with the invention;

FIG. 2 is a partial and elevational and partial sectional view of a heater indicated in FIG. 1;

FIG. 3 is a partial end elevational view of another embodiment of a space heater having a fuel system operated by an interrupter circuit controlled by rotation of the fan motor for the combustion air; and v FIG. 4 is a schematic elevational view of the interrupter circuit for operating the fuel pump for the fuel supply.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in particular, the invention embodied therein comprises a space heater generally designated 20 which includes an air compressor or blower l which is driven from an electric motor 22 which is mounted in a casing 24 affixed to one end of a housing generally designated 26.

In accordance with the invention the housing 26 is of relatively flat construction, that is, it has a relatively slight thickness and it is axially elongated with the dimensional proportions being substantially as indicated by the drawings. The widest portion of the construction includes the centrally arranged casing 24 for the motor 22 and blower l and this is arranged along the axis at one end of the casing 26. Air for combustion is drawn into an inlet 28 by the blower l and discharged into a combustion chamber 2 which is also arranged along an axial central line and which may be widened in a cylindrical manner comparable to the casing 24. Fuel for combustion is directed first into an antechamber or precombustion chamber 6 which extends radially inwardly to the combustion chamber 2 and discharges the combustion products with the fuel into the combustion chamber 2. Suitable ignition means (not shown) may also be provided in the precombustion chamber 6.

The gaseous products of combustion are directed as indicated by the arrow 30 in a substantially axial direction into an axially arranged combustion air flow inner housing or heat exchanger generally designated 32 which is arranged within the outer housing 26 and of substantially the same flat outline as the housing 26.

As shown in the drawings, portions of the combustion products may flow in transverse directions as indicated by ar rows 34 and 36 and around cross passages 38 through which the air to be heated may be passed.

A further feature of the construction is the configuration of the outer housing 26 which defines an annular passage 5 for the air to be heated. The air or other medium to be heated is directed into the casing 26 from opposite ends into fittings 8 and 10 arranged at one side of the housing 26 and it may pass through the annular chamber'S' to either side of the centrally arranged inner combustion gas housing 32 and be discharged outwardly through the fittings 9 and 11 on the opposite side. The construction permits a counterflow of the heating air in respect to the temperature of the combustion gases and also some parallel flow or mixed flow. Portions of the air to be heated which enter through the fitting 10, for example, may be diverted into the annular space 50 which directly surrounds the combustion chamber 2 and additional portions may flow, for example, through the passages 38 which extend through the interior housing 32. The combustion gases which have given up their heat are directed outwardly through the discharge conduit 4. I

As shown in FIGS. 3 and 4, a known type electromagnetic piston pump 70 is connected to the motor 22. so that its operation can be controlled by an interrupter generally designated 72 driven by the motor to provide a suitable fuel flow to the precombustion chamber 6' in order that the heater device may operate at optimum efficiency. The pump 70 has a discharge 74 connected to the inlet 76 of the chamber 6'.

The interrupter 70 comprises a cam 78 mounted on motor shaft 80 which is rotated by motor 22. The motor 22' also drives the combustion air fan (not shown). The cam 78 moves a moveable contact arm 82'which makes and breaks contact with a fixed contact 84 of a power circuit connected to supply power to the pump 70. The pump 70 is an electromagnetic piston pump and it is given an operating pulse from the power supply or battery 86 in timed relationship to the rotation of the shaft 80 of the motor 22'. In this manner, fuel is delivered by the pump 70 from a suction line to the supply 76.

lclaim:

l. A space heater comprising an outer flat space heater housing, inlet means adjacent one side of said housing and outlet means adjacent the opposite side of said housing for the inflow and outflow of a medium to be heated, an inner combustion gas housing of substantially .the same overall configuration as said outer housing spaced inwardly from the interior of said outer housing and extendingaxially therethrough and defining: combustion chamber means adjacent one end, an intermediate heat exchange passage for the combustion gas products and a discharge passage atthe Opposite end; combustion air delivering means centrally mounted on said outer housing adjacent said combustion chamber for discharging combustion air into said combustion chamber means, means for delivering fuel for ignition into said combustion chamber means, said means for delivering fuel for ignition in said combustion chamber means including an electromagnetic piston pump, said combustion air delivering means comprising a rotatable electric motor, and an interrupter driven by said motor and connected to said electromagnetic piston pump for actuating said pump in timed relationship to rotation of said motor.

2. A space heater, according to claim I, wherein said combustion chamber means includes a central axially extending combustion chamber and a precombustion chamber connected into said combustion chamber, said means for delivering fuel for ignition being connected to said precombustion chamber.

3. A space heater, according to claim 1, wherein said combustion air delivering means includes a rotary fan connected to discharge axially into said combustion chamber, said electric motor being centrally mounted on said outer housing and connected to said fan for rotating said fan.

4L A space heater, according to claim 1 wherein said inner combustion gas housing includes a central cylindrical portion and a flat portion extending outwardly from respective opposite sides of said cylindrical portion, said combustion gas housing having an axial dimension substantially greater than the transverse dimension.

5. A space heater, according to claim 4, wherein said inner housing has a plurality of passages extending therethrough communicating with the space between said inner and outer housing.

6. A space heater, according to claim 1, wherein said inlet means includes a connection adjacent each end of each outer housing to the space within said outer housing between said inner and outer housing.

7. A space heater, according to claim 1, wherein said outlet means includes a connection for the outflow of the medium to be heated located adjacent each end of said outer housing.

8. A fuel supply system operable by an electric combustion air motor for a space heater, comprising an electromagnetic piston driven fuel pump, an electrical circuit connected to said fuel pump; including a power source, a rotatable member adapted to be rotated by the electric combustion air motor, and an interrupter connected between said power source and said fuel pump and moved by said rotatable member to periodically connect and disconnect said power source to said pump for driving said pump piston to deliver fuel in timed relation to the operation of said electric combustion air motor, a combustion chamber, an electric combustion air motor connected to said rotatable member to rotate said member, and a combustion air fan driven by said electric motor for providing a combustion air to said combustion chamber, said pump having a discharge connected to discharge fuel into said combustion chamber. 

1. A space heater comprising an outer flat space heater housing, inlet means adjacent one side of said housing and outlet means adjacent the opposite side of said housing for the inflow and outflow of a medium to be heated, an inner combustion gas housing of substantially the same overall configuration as said outer housing spaced inwardly from the interior of said outer housing and extending axially therethrough and defining: combustion chamber means adjacent one end, an intermediate heat exchange passage for the combustion gas products and a discharge passage at the opposite end; combustion air delivering means centrally mounted on said outer housing adjacent said combustion chamber for discharging combustion air into said combustion chamber means, means for delivering fuel for ignition into said combustion chamber means, said means for delivering fuel for ignition in said combustion chamber means including an electromagnetic piston pump, said combustion air delivering means comprising a rotatable electric motor, and an interrupter driven by said motor and connected to said electromagnetic piston pump for actuating said pump in timed relationship to rotation of said motor.
 2. A space heater, according to claim 1, wherein said combustion chamber means includes a central axially extending combustion chamber and a precombustion chamber connected into said combustion chamber, said means for delivering fuel for ignition being connected to said precombustion chamber.
 3. A space heater, according to claim 1, wherein said combustion air delivering means includes a rotary fan connected to discharge axially into said combustion chamber, said electric motor being centrally mounted on said outer housing and connected to said fan for rotating said fan.
 4. A space heater, according to claim 1 wherein said inner combustion gas housing includes a central cylindrical portion and a flat portion extending outwardly from respective opposite sides of said cylindrical portion, said combustion gas housing having an axial dimension substantially greater than the transverse dimension.
 5. A space heater, according to claim 4, wherein said inner housing has a plurality of passages extending therethrough communicating with the space between said inner and outer housing.
 6. A space heater, according to claim 1, wherein said inlet means includes a connection adjacent each end of each outer housing to the space within said outer housing between said inner and outer housing.
 7. A space heater, according to claim 1, wherein said outlet means includes a connection for the outflow of the medium to be heated located adjacent each end of said outer housing.
 8. A fuel supply system operable by an electric combustion air motor for a space heater, comprising an electromagnetic piston driven fuel pump, an electrical circuit connected to said fuel pump; including a power source, a rotatable member adapted to be rotated by the electric combustion air motor, and an interrupter connected between said power source and said fuel pump and moved by said rotatable member to periodically connect and disconnect said power source to said pump for driving said pump piston to deliver fuel in timed relation to the operation of said electric combustion air motor, a combustion chamber, an electric combustion air motor connected to said rotatable member to rotate said member, and a combustion air fan driven by said electric motor for providing a combustion air to said combustion chamber, said pump having a discharge connected to discharge fuel into said combustion chamber. 